On the other hand I have a request: Could you please stop deleting old ebuilds the same moment a newer is pushed? It is very annoying to test a new kernel just to see it being removed only a few days later. Please keep those ebuilds around for a while if that's possible.
If you are worried about the space, you could use bzip2 on the patches in your files dir. Using bzip2 reduces the space needed for files/3.7.5 on my system from 31M to 6.5M. (and 4.7M with 7z.) Just pipe-unpack them back in.
(Note: I do not know whether this works reliably from an ebuild, but if I have to patch anything and the patch is a tarball, "tar xjf foo.tar.bz2 -O | patch" normally works.)

This was somehow weird and scary for me: I had compiled nvidia-drivers-313.18 modules successfully for
linux-3.7.5.X
where X are ca 90 patches from G.K-H stable-queue at their way to release.6. Then - this morning - the released linux failed _________________fun2gen2

Given a piece of the log does not say anything. Where is USE flags and full logs? As I can see dumpstack.c in 3.7.7 patch only: debian, grsecurity, pld, suse. As in my view pld not look very good. And If the problem in grsecurity then even more you know what awaits you.

However, although zen is patched in first, the zen configuration options do not show up in the menu. Any idea, why? (Skipped are: misc-3.8-20130303.patch and zswap-3.8-20130303.patch)_________________systemd - The biggest fallacies

Do they have a use flag, now? I am still trying to get zen options to show up. The patches go through, but nothing so far. (To get BFS back, I had to re-enable ck USE flag.)_________________systemd - The biggest fallacies